The programme catalogues, names, and conserves sites of outstanding cultural or natural importance to the common heritage of humanity. Under certain conditions, listed sites can obtain funds from the World Heritage Fund. The program was founded with the Convention Concerning the Protection of the World's Cultural and Natural Heritage,[3] which was adopted by the General Conference of UNESCO on 16 November 1972. Since then, 191 states parties have ratified the Convention, making it one of the most adhered to international instruments. Only Liechtenstein, Nauru, Somalia, South Sudan, Timor-Leste, and Tuvalu are not Party to the Convention.

As of July 2015, 1031 sites are listed: 802 cultural, 197 natural, and 32 mixed properties, in 163 states parties.[4][5] According to the sites ranked by country, Italy is home to the greatest number of World Heritage Sites with 51 sites, followed by China (48), Spain (44), France (41), Germany (40), Mexico (33), and India (32). UNESCO references each World Heritage Site with an identification number; however, new inscriptions often include previous sites now listed as part of larger descriptions. Consequently, the identification numbers exceed 1,200, even though there are fewer on the list.

While each World Heritage Site remains part of the legal territory of the state wherein the site is located, UNESCO considers it in the interest of the international community to preserve each site.

In 1954, the government of Egypt decided to build the new Aswan High Dam, whose resulting future reservoir would eventually inundate a large stretch of the Nile valley containing cultural treasures of ancient Egypt in Nubia. In 1959, the governments of Egypt and Sudan requested UNESCO to assist their countries to protect and rescue the endangered monuments and sites. In 1960, the Director-General of UNESCO launched an appeal to the Member States for an International Campaign to Save the Monuments of Nubia.[6] This appeal resulted in the excavation and recording of hundreds of sites, the recovery of thousands of objects, as well as the salvage and relocation to higher ground of a number of important temples, the most famous of which are the temple complexes of Abu Simbel and Philae. The campaign, ended in 1980, was considered a complete and spectacular success. As tokens of its gratitude to countries which especially contributed to the campaign's success, Egypt donated four temples: the Temple of Dendur was moved to Metropolitan Museum of Art in New York City, the Temple of Debod was moved to Parque del Oeste in Madrid, the Temple of Taffeh was moved to Rijksmuseum van Oudheden in the Netherlands, and the Temple of Ellesyia to Museo Egizio in Turin.[7]

The project cost US$80 million, about $40 million of which was collected from 50 countries. The project's success led to other safeguarding campaigns: saving Venice and its lagoon in Italy, the ruins of Mohenjo-daro in Pakistan, and the Borobodur Temple Compounds in Indonesia. UNESCO then initiated, with the International Council on Monuments and Sites, a draft convention to protect the common cultural heritage of humanity.

The United States initiated the idea of cultural conservation with nature conservation. A White House conference in 1965 called for a "World Heritage Trust" to preserve "the world's superb natural and scenic areas and historic sites for the present and the future of the entire world citizenry". The International Union for Conservation of Nature developed similar proposals in 1968, and they were presented in 1972 to the United Nations conference on Human Environment in Stockholm. Under the World Heritage Committee signatory countries are required to produce and submit periodic data reporting providing the World Heritage Committee with an overview of each participating nation's implementation of the World Heritage Convention and a "snapshot" of current conditions at World Heritage properties.

A single text was agreed on by all parties, and the "Convention Concerning the Protection of the World Cultural and Natural Heritage" was adopted by the General Conference of UNESCO on 16 November 1972.

A country must first inventory its significant ethical and natural properties; the result is called the Tentative List. A country may not nominate properties that have not been included on the Tentative List. Next, it can place properties selected from this list into a Nomination File.

The Nomination File is evaluated by the International Council on Monuments and Sites and the World Conservation Union. These bodies then make their recommendations to the World Heritage Committee. The Committee meets once per year to determine whether or not to inscribe each nominated property on the World Heritage List and sometimes defers the decision to request more information from the country which nominated the site. There are ten selection criteria – a site must meet at least one of them to be included on the list.[citation needed]

Until the end of 2004, there were six criteria for cultural heritage and four criteria for natural heritage. In 2005, this was modified so that there is only one set of ten criteria. Nominated sites must be of "outstanding universal value" and meet at least one of the ten criteria.[9]

"represents a masterpiece of human creative genius and cultural significance"

"exhibits an important interchange of human values, over a span of time, or within a cultural area of the world, on developments in architecture or technology, monumental arts, town-planning, or landscape design"

"to bear a unique or at least exceptional testimony to a cultural tradition or to a civilization which is living or which has disappeared"

"is an outstanding example of a type of building, architectural, or technological ensemble or landscape which illustrates a significant stage in human history"

"is an outstanding example of a traditional human settlement, land-use, or sea-use which is representative of a culture, or human interaction with the environment especially when it has become vulnerable under the impact of irreversible change"

"is directly or tangibly associated with events or living traditions, with ideas, or with beliefs, with artistic and literary works of outstanding universal significance"

"is an outstanding example representing major stages of Earth's history, including the record of life, significant on-going geological processes in the development of landforms, or significant geomorphic or physiographic features"

"is an outstanding example representing significant on-going ecological and biological processes in the evolution and development of terrestrial, fresh water, coastal and marine ecosystems, and communities of plants and animals"

"contains the most important and significant natural habitats for in-situ conservation of biological diversity, including those containing threatened species of outstanding universal value from the point of view of science or conservation"

"Article 53. PROTECTION OF CULTURAL OBJECTS AND OF PLACES OF WORSHIP. Without prejudice to the provisions of the Hague Convention for the Protection of Cultural Property in the Event of Armed Conflict of 14 May 1954,' and of other relevant international instruments, it is prohibited:[11]

(a) To commit any acts of hostility directed against the historic monuments, works of art or places of worship which constitute the cultural or spiritual heritage of peoples;

There are 981 World Heritage Sites located in 160 States Party. Of these, 759 are cultural, 193 are natural and 29 are mixed properties. The World Heritage Committee has divided the world into five geographic zones which it calls regions: Africa, Arab States, Asia and the Pacific, Europe and North America, and Latin America and the Caribbean.

Russia and the Caucasus states are classified as European, while Mexico is classified as belonging to the Latin America & Caribbean zone, despite its location in North America. The UNESCO geographic zones also give greater emphasis on administrative, rather than geographic associations. Hence, Gough Island, located in the South Atlantic, is part of the Europe & North America region because the government of the United Kingdom nominated the site.

The table below includes a breakdown of the sites according to these zones and their classification:[12][13]